* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #71b7e6, #9b59b6);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 20px;
}

/* 新增：页面标题样式 */
header {
    width: 100%;
    max-width: 400px;
    text-align: center;
    margin-bottom: 20px;
}

.page-title {
    font-family: 'Poppins', sans-serif; /* 使用更好看的字体 */
    font-size: 45px; /* 增大字体大小 */
    font-weight: 700; /* 使用更粗的字体重量 */
    color: #fff;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
    letter-spacing: 20px; /* 增加字间距 */
}

.container {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 10px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
    width: 400px;
    max-width: 95%;
    overflow: hidden;
    padding: 20px;
    position: relative;
}

.tabs {
    display: flex;
    margin-bottom: 20px;
}

.tab {
    flex: 1;
    text-align: center;
    padding: 15px 0;
    cursor: pointer;
    background: #f7f7f7;
    transition: background 0.3s;
    font-weight: bold;
    color: #555;
    border-radius: 5px 5px 0 0;
    margin-right: 2px;
}

.tab:last-child {
    margin-right: 0;
}

.tab.active {
    background: #fff;
    border-bottom: 2px solid #9b59b6;
    color: #9b59b6;
}

.form-container {
    padding: 20px;
    background: #fff;
    border-radius: 0 0 10px 10px;
}

form {
    display: none;
    animation: fadeIn 0.5s ease-in-out;
}

form.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.form-group {
    margin-bottom: 15px;
    position: relative;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    color: #333;
}

.form-group input {
    width: 100%;
    padding: 10px 15px;
    border: 1px solid #ccc;
    border-radius: 5px;
    transition: border 0.3s;
    font-size: 16px;
}

.form-group input:focus {
    border-color: #9b59b6;
    outline: none;
}

.form-group .toggle-password {
    position: absolute;
    right: 15px;
    top: 38px;
    cursor: pointer;
    color: #9b59b6;
    font-size: 14px;
    user-select: none;
}

.submit-btn {
    width: 100%;
    padding: 10px;
    background: #9b59b6;
    border: none;
    border-radius: 5px;
    color: #fff;
    font-size: 16px;
    cursor: pointer;
    transition: background 0.3s;
}

.submit-btn:hover {
    background: #8e44ad;
}

.error-message {
    color: #e74c3c;
    font-size: 14px;
    margin-top: 5px;
    display: none;
}

.success-message {
    color: #2ecc71;
    font-size: 14px;
    margin-top: 5px;
    display: none;
}

@media (max-width: 500px) {
    .container {
        width: 95%;
    }
    .page-title {
        font-size: 28px; /* 小屏幕下适当减小标题字体大小 */
    }
}